Choosing a substrate

Hey all, I'm redoing a small 20L tank, and want to get things right from the off!
I'm wondering what substrates people would recommend? I need about 3L/KG, and have therefore ruled out ecocomplete because I'd be using less than 1/3 of a bag and have no use for the rest.
As far as I can see my choices are:
ADA Aqua Soil - 3L
JBL AquaBasis plus - 2.5L
TetraPlant Complete Substrate - 2.8kg
Tropica Plant Substrate - 2.5L

So yeah, any clear winners out of these, or recommendations?
Also, I have no intention of covering it with silica sand or anything, so are any of these unsuitable for using exclusively?

Also looking at an 11W Arcadia Arc Pod, which would give me 2.5WPG. Is this the best option for me, lightwise? Is there anything better for the same price, or anything just as good for a cheaper price?
Would that level of light be sufficient for HC Cuba, with good CO2 and ferts?